Wondering if debris has found its way into that one zone.

That was one of my thoughts. But, one of my zones in the back has an open 1" pipe that has nothing attached to it (redoing the zone after a septic system upgrade) and the same thing happens when I transfer to that zone. One thought that I have is that my water pump to my well might need replaced. That it can't keed up with the demand of the transfer. When it transfers from the last zone in the front to any of the zones in the back, there isn't enough pressure in my sprinkler system main line to compensate for what is need to hold the PVB open and fill the zone with water and pressurize the sprinkler heads enough to get them to pop-up. I have an new well pump install scheduled for Monday the 6th of May. I also have a holding tank with an air diaphram that I will have looked at. It is suppose to keep my water system for my house pressurized. If any one is interested, I will post the results after the new pump is installed.

The new pump and motor was installed Monday. I checked the sprinkler system after running a garden hose for about an hour to clear any rust particles. The system transfered like it is suppose to. I upgraded my pump from 1/2 HP to 3/4 HP, but I was told to do this I needed to install a larger bladder tank, so I am having a 10 gal. tank added to my water system. By going with a larger pump/motor and without adding to the bladder tank (storage), the motor will turn on and off more often, shortening the life of the pump motor. I was told what happens is that the switch from the start windings to the run windings in the motor goes bad, so it is best to have the pump motor turn on and stay on.

interesting... so is the system back up and running to design specs with the new equipment?

Yes, the system was up and running very well. During the dry month of July I had one of the only green yards around. Recently my timer got fried, lightening? Need to replace so I can winterize system. Installation should go smooth once it is bought.

I had a hard time getting a new timer so late in the season. I went to Home Depot because they seem to have a nice variety of Toro products when I was redoing some of the zones. It was too late in the season for them to have a timer in stock so I opted to buy on ebay. I won the auction at the beginning of Nov. and din't get the timer until the middle of Dec. I had hoped for quick shipping for the ebayer that sold the timer to me but was disappointed. On top of slow shipping, the power supply didn't work. I had to wait for the supplier to ship me another one. That took another month, so now I am ready to winterize my sprinkler system in the beginning of Jan. We hadn't had a really hard freeze up to this point so I was optimistic that my pipes weren't damaged too badly. There was a break in the weather and I was able to blow them out. I did buy an electric heat tape to keep the exposed pipe that was above ground from freezing. I'll see what the damage was this Spring when I start the system up again. I'm sure I won't have the work I had last Spring with repairing half my zones because of a new septic system install.
Happy Watering

I have the same problem listed above. Two stations go nuts when they turn on. Water shoots out the top of the PVB and I by turning the valve on and off, I can get the water to go through to the sprinklers. What could the issue be, it's driving me crazy. What steps do I need to try to fix the issue?

Help me! I am having the same problem. I just had the system completely redone and can't even put the system on it's timer because I'm afraid that gallons of water will gush from the PVB when I am sleeping. The "irrigation guys" said there isn't enough pressure-- so I had it checked and it's over 80 lbs.(plenty). The "guys" said that I must have been running the washing machine or flushing the toilet (which I wasn't)! Besides, is he saying I can't flush the toilet and run the sprinkler! His solution is to have a new valve (a backflow)put directly into the water line in the basement. Is he laying this on me and having me hire a plumber? Or is it legit?